ACL Injuries: Risk Factors

July 27, 2018

Injury prevention starts with risk factor identification. A
spate of high profile metatarsal fractures in the late 90’s and early 2000’s
for footballs lead to the identification that less supportive footwear was a
primary cause of these fractures. This year rugby has change the rules for
tackling to lower the risk of head and neck injuries, after higher tackles were
identified as a cause of concussions. The necessity of having rest days as part
of an athletes training program came from evidence of overtraining symptoms
having both psychological and physical effects on the athlete. Athletes
including strength training as part of their training programs as muscular
imbalances and weakened muscles were shown to lead to injuries as well as aid
performance.

Once you identify risk factors you can create training
programs, alter athletes’ footwear and sporting equipment, optimise their diet
and modify sporting techniques to decrease injury rates. In ACL ruptures there
are two main types of injuries – contact and non-contact ruptures. IN contact
ruptures an external force is applied to the athletes’ knee and this tears the
ACL. In football, tackling the studs up, or going over the ball have been
banned for this reason.

In non-contact injuries the athletes turns and pushes off in
a manner that places an excessive force through their ACL, leading to it
tearing. The risk factors for this type of injury can by divided into two main
groups; biomechanical risk factors and anatomical/hormonal factors. Anatomical
risk factors require sophisticated equipment to identify the deficits, but have
little to no solutions to rectify these issues. Hormonal risk factors are
debatable at present, there is some evidence that menstrual cycle phase may
play a role in injury rates. However it is not conclusive enough warrant
restricting athletes from exercise during certain stages

Biomechanical risk factors have shown the most potential for
immediate and significant reductions in in injury rates if corrected through
training strategies. These factors include; landing with less knee and hip
flexion, altered muscle activation patterns, increase twisting of the knee
inwards on landing from a jump while the foot is pointing outwards, decreased
hamstring activation and less knee joint stiffness. This have all been recorded
more frequently in women than men – explaining the high risk of ACL ruptures
for young females. Women also demonstrated a pattern of limb dominance, where
there is an asymmetry between their left and right leg strength, flexibility
and coordination that results in an increase risk factor for the weaker leg.

Now that we know the risk factors that lead to ACL ruptures,
we can create training programs to correct these issues.